Serial console is available on JP2 connector ​(look at the picture of PCB).\\

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Serial console is available on the JP2 (v1.x) or J1 (v2.0) connector - see PCB photos above.

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Setting: 115200 8N1\\

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Login to factory ​firmware: ​root/5up\\

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**DO NOT CONNECT VCC**. Use only TX/​RX/​GND.

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Baud Rate: 115200\\

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Data Bits: 8\\

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Parity: No\\

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Stop Bits: 1\\

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Factory ​firmware ​login credentials: //(v1.x only)//\\

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* username: root\\

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* password: 5up

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''​Note:''​ be extremely careful when soldering a serial console on TP-Link TL-WDR4900 - the design of the PCB is not well suited for soldering and important paths/​connections are near the soldering points. We have now 3 Routers which are dead, just because we used too much solder...

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===== Installation =====

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OpenWRT may be installed [[doc/​howto/​generic.flashing#​method.1via.oem.firmware|via OEM firmware]] on both versions.

* If you do not speak chinese and are not familiar with the standard TP-Link firmware, please see the screen shots below for help.

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After installation you will want to proceed with [[http://​wiki.openwrt.org/​doc/​howto/​firstlogin|first login]], [[http://​wiki.openwrt.org/​doc/​howto/​basic.config|basic configuration]]. You may also wish to install the web user interface [[doc/​howto/​luci.essentials|LuCI]],​ after which you can manage your router at http://​192.168.1.1

- When you see ''​Autobooting in 1 seconds'',​ quickly type "''​tpl''" ​to access the command line.

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* there is no harm at all typing "''​tpl''"​ repeatedly from the moment you power on, I often start when I see the U-Boot bootloader header. ​;-)

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- Start the TFTP server running ​on your computer.

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- At the ''​ap135>''​ prompt, type the following commands:

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- ''​tftpboot 0x81000000 openwrt.bin''​ (where openwrt.bin is the name of your firmware image)

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- ''​erase 0x9f020000 +0x7c0000''​

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- ''​cp.b 0x81000000 0x9f020000 0x7c0000''​

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- ''​bootm 0x9f020000''​

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- Congratulations!

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There are significant issues with Barrier Breaker, as of 08-June-2013. You can use the 2.4 GHz wireless, but you cannot authenticate ​to the 5 GHz. Other issues include ​that the WAN port stops grabbing ​DHCP addresses. Some builds work some of the time.

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==== Reset Button Method (no serial cable needed) ====

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If you want to de-brick/​upgrade your router using TFTP without a serial cable follow these steps:

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=== Pre-requisites ===

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* Copy a working & full OpenWrt sysupgrade image into your TFTP server folder (e.g: https://​downloads.openwrt.org/​barrier_breaker/​14.07/​mpc85xx/​generic/​openwrt-mpc85xx-generic-tl-wdr4900-v1-squashfs-sysupgrade.bin) so it will be found under the path /​wdr4900v1_tp_recovery.bin ​You can also use the image used for reverting to stock firmware if you prefer to do so, but it has to be placed under the same path.

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* A TFTP server started on your local machine on LAN address 192.168.0.66/​24.

- Copy your desired openwrt image for the TPlink-WDR4900 into your TFTP server folder and rename it into ''​wdr4900v1_tp_recovery.bin''​ (as the router will search for this file).

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- Make sure your card has address 192.168.0.66.

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- Start the tftp server and make sure it is listening on 192.168.0.66

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- Plug in your router and keep the WPS/Reset button pressed until the tftp server confirms the transfer is done

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- Wait for the router to reboot, the new image will then be loaded

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- A pack ready for doing this, containing TFTPD32 server and the latest TP-Link firmware, can be found here: https://​forum.openwrt.org/​viewtopic.php?​pid=236428#​p236428

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- Also there'​s a video of the process: http://​www.youtube.com/​watch?​v=54PAS0gvW2k

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===== Failsafe / reset =====

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On the v1 units, the only way that I have been able to get the router into failsafe mode is to quickly and repeatedly press the WPS/Reset button //starting before the front panel "​star"​ LED started flashing. //When that LED finally lit, it appeared to go directly into the rapid-flashing "​failsafe"​ indication. If the WPS LED lights (rightmost, "​yin-yang arrows"​),​ it may be that you started clicking the button a little early in the boot sequence.

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For what you can do in failsafe, go to the [[doc:​howto:​generic.failsafe|OpenWrt Failsafe Mode]] page.

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Another user writes:

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> After all else failed, I found [[http://​www.binaryfriend.ru/​2012/​10/​how-to-hard-reset-openwrt-on-tp-link-1043nd]]. ​ Extremely simple. ​ Please see the original page for more info. Summary:

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>

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> - Power the router up;

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> - After powering up track the SYS light when it starts to blink, when it does press and hold the QSS button till SYS lights starts to blink faster – router goes to recovery mode;

Note: You can only flash this firmware version because it has no BOOT in the filename. This image and OpenWRT images are the exact same size. Other images from TP-Link do have BOOT in the filename and these files are also

Note: You can only flash this firmware version because it has no BOOT in the filename. This image and OpenWRT images are the exact same size. Other images from TP-Link do have BOOT in the filename and these files are also

Numbers 2-5 are Ethernet Ports 1-4 as labeled on the unit, number 1 is "​Internet"​ (WAN) on the unit, 0 is the internal connection to the router itself.

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^ Port ^ Switch port ^

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| CPU | 0 |

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| WAN | 1 |

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| LAN 1 | 2 |

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| LAN 2 | 3 |

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| LAN 3 | 4 |

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| LAN 4 | 5 |

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| (not used ?) | 6 |

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==== Switch Ports (for VLANs) ==== WDR4900 v2

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Numbers 2-5 are Ethernet Ports 1-4 as labeled on the unit, number 1 is "​Internet"​ (WAN) on the unit, 6 is the internal connection to the router itself, and 0 is another CPU, because this router has two.

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^ Port ^ Switch port ^

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| Second CPU | 0 |

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| WAN | 1 |

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| LAN 1 | 2 |

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| LAN 2 | 3 |

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| LAN 3 | 4 |

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| LAN 4 | 5 |

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| CPU | 6 |

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==== Luci WDR4900v2 (Example Vlans tag for Movistar FTTH Spain)

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{{:​media:​tplink_wdr4900v2_switch_vlan_tagg.jpg?​900}}

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==== Port Mirroring ====

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Hardware port mirroring is supported in v1/(v2?) FIXME

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Here's an example of configuring port mirroring in /​etc/​config/​network for mirroring port 1 to port 5

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(You may need to restart the router for port mirroring changes to take effect):

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<​code>​

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config switch

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option name '​switch0'​

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option reset '​1'​

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option enable_vlan '​1'​

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option enable_mirror_rx '​1'​

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option enable_mirror_tx '​1'​

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option mirror_source_port '​1'​

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option mirror_monitor_port '​5'​

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</​code>​

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===== QEMU test environment =====

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In case you are interested to run a virtual test environment for your PPC based WDR4900 platform

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QEMU is a good helper. It cannot run the downloadable kernel image but at least a slightly modfied

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version. Here are the basic steps to get a initial setup up and runnung.

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Install QEMU for your Linux distribution. It should be at least 2.1.2. The process was only tested

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with that version. Create a [[about:​toolchain|buildroot environment]]. If you do not want to read

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every single bit of information over there use these commands. We assume that we only want to

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build the stable Barrier Breaker version.

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<​code>​

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# cd ~

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# mkdir buildroot

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# cd buildroot

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# git clone git://​git.openwrt.org/​14.07/​openwrt.git

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# cd openwrt

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# ./​scripts/​feeds update -a

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# ./​scripts/​feeds install -a

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</​code>​

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Select your target platform

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<​code>​

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# make menuconfig

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Target System -> Freescale MPC85xx [*]

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</​code>​

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Save changes and leave setup. Create the default configuration for the platform

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<​code>​

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# make defconfig

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</​code>​

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Activate some essential buildroot configuration options.

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<​code>​

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# make menuconfig

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Target images -> ramdisk [*]

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Kernel modules -> filesystems -> kmod-fs-ext4 [*]

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</​code>​

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Save changes and leave setup. Now head over to kernel configuration and define critical